I have a short piece in today's New York Times about how male swallows are evolving longer tails, which female swallows find sexy. Here's the original paper in press at The Journal of Evolutionary Biology. Measuring the effects of natural selection is tough work, the details of which are impossible to squeeze into a brief news article. Scientists have to document a change in a population of animals--the length of feathers, for example--but then they have to determine that the change is a product of genetic change. We are much taller than people 200 years ago, but it's clear that most, if not all, of this change is simply a response of our bodies to better food and medicine. The authors of the swallow paper carried out a number of studies that suggest that the length of swallow tails is genetically based, and that those genes are changing. If they're right--and other experts I contacted think they are--it's a striking example of how quickly the sex lives of wild animals can evolve.

Things get a little fuzzier when the researchers propose what's driving the evolution. They think desertification in the springtime range of the swallows in Algeria is to blame. But it's very hard to eliminate other possibilities, since these swallows have complicated lives, migrating from Europe to South Africa and back every year. It's much easier to make a case for the forces driving the evolution of Darwin's finches, which generally sit obediently on the island on which they were born and are subject to cycles of droughts and heavy rains.

But it's a question very much worth investigating. Global warming may well produce ecological changes that could produce just these sorts of rapid evolutionary changes in animals and plants. In some cases, species may be able to adapt quickly enough to their new environment. In other cases, they may lose the race.

On Wednesday I spoke on "The Current," the Canadian Broadcasting Corporation's morning radio show. The hour-long segment focuses on various aspects of evolution, such as the evolution of diseases and the ongoing creationist circus in Georgia. I spoke about how humans are altering the evolution of other species. You can listen to the entire episode here. The audo file is broken up into pieces; part two and part three are the evolution segment.

Last month saw the bombshell report that a tiny species of hominid lived on an Indonesian island 18,000 years ago. Since then there has been a dribbling of follow-up news. Some American paleoanthropologists have expressed skepticism, pointing out that while bones from several small individuals have been found, only one skull has turned up. The skull was the most distinctive part of the skeleton, with a minuscule brain and other features that suggested it was not closely related to our own species. The skeptics suggest that these hominids were actually modern human pygmies, and that the skull came from an individual who suffered a genetic disorder called microcephaly.

In Friday's issue of Science, Michael Balter reports that a prominent Indonesian anthropologist, Teuku Jacob of Gadjah Mada University, thinks Homo floresiensis was a microcephalic. He has taken possession of the fossils to study them, and this has a number of researchers worried. Jacob is known to guard fossils in his vault, and so he may essentially be making it impossible for other researchers to look at them. Balter quotes one of the authors of the original report on the fossils, Peter Brown of the University of New England in Australia, saying, "I doubt that the material will ever be studied again."

This could be staggeringly tragic, because the world is waiting for the other shoe to drop: is there any DNA in the fossils?

The fossils are so young that they might well contain some genetic fragments, and this DNA could quickly resolve the debate over which species the bones belong to. If they belong to human pygmies, their DNA should be more similar to the DNA of Australian aborigines or Southeast Asians than to Europeans or Africans. But if, as Brown and his colleagues suggest, they belong to a species that branched off from an Asian population of Homo erectus, then their DNA should not be particularly close to any living human's genes. Most evidence indicates that Homo erectus in Asia shares a common ancestor with Homo sapiens that lived two million years ago. It might even be possible to compare Homo floresiensis DNA to the fragments of Neanderthal DNA that have come to light in recent years. If Brown is right, then Neanderthal DNA should be more similar to human DNA than that of Homo floresiensis, because Neanderthals and humans share a common ancestor that lived roughly 500,000 years ago--four times younger than the ancestor we share with Homo erectus.

According to an Australian newspaper, Brown and his colleagues have found hair that may belong to H. floresiensis, and which may contain DNA. But if that turns out to be a dead end, the next best hope will be the fossils. And the biggest challenge in finding fossil hominid DNA is contamination. You don't want to accidentally grab DNA from a lab assistant's thumbprint. If the Homo floresiensis goes down a bureaucratic rabbit hole, that challenge could become enormous.

In tomorrow's issue of the New York Times, I have an essay that grew out of a meeting I went to earlier this month on natural history illustrations through the ages. The essay is accompanied by some of the cooler images I saw there, some of which are also included in the web version. Here's one that wasn't--one of the first illustrations of the legendary Victoria Regia water lily, so big that a single leaf could support a grown man. I explain in the essay why this picture was the 1854 equivalent of a high-resolution digital scan.

There are lots of news stories today (as well as PZ Myers' take) about the fabulous new discovery in Spain of Pierolapithecus catalaunicus, a 13-million year old fossil close to the common ancestor of all living great apes.

The early evolution of apes is where some of the most interesting developments are emerging. Until the recent discoveries of fossils of Pierolapithecus catalaunicus and other early species, the fossil record from this period of our history was pretty scanty. These new fossils are starting to shed light on some pretty major questions, such as how our upright stance came to be and how our brains got so big. Meanwhile, new genetic work is raising the curtain on the evolution of cognition in these early apes, which set the stage for our subsequent explosion.

Yet for all the excitement a story like can engenders, some of the coverage has been pretty irritating. Certain hoary misconceptions about science have a way of taking hold in the journalistic world and seem to be impossible to dislodge. One of these is the notion that paleoanthropologists are focused on discovering "the missing link," and that only the missing link can tell us anything of real importance about our origins. Just consider Diedtra Henderson's article on MSNBC.com. It includes this rather revealing sentence--

"Coaxed by a reporter to say Pierolapithecus catalaunicus represented a 'missing link,' co-author Meike Kohler demurred. 'I don’t like, very much, to use this word because it is a very old concept.'"

That's right--coaxed. As in, "Come on, professor, just give us a smile and say it's a missing link. It won't kill you, right?"

Henderson is hardly alone. A little googling unearths 59 articles that do their best to call Pierolapithecus a missing link, even if it means putting a question mark after it in a headline. Today, Ira Flatow on Science Friday asked his paleoanthropologist guest whether the fossil is a missing link, even while he acknowledged that the scientist might not want to be "boxed in" with that phrase.

Now, if you learned about human origins 50 years ago, you might well have read things by scientists referring to a missing link in our evolution. The great paleoanthropologist Robert Broom even published a book in 1951 called Finding the Missing Link. But this was a time when so few fossils were known from human evolution that many researchers thought that our ancestry was pretty much linear until you got back to our common ancestor with other living apes. But fifty years later, it's abundantly clear now that human evolution has produced many branches, all but one of which have ended in extinction. Some are close to our own ancestry, others are further away. Paleoanthropologists don't get excited about a fossil because they think they've found the missing link (whatever that is), but because a fossil can show how early a trait such as a big brain evolved, and sometimes can even reveal traits that have evolved independently several times in evolution. That's what gets them fired up about Pierolapithecus catalaunicus. So why shouldn't journalists get fired up as well, rather than trotting out old cliches?

It's not just lazy journalism, I'd argue, but abets some pernicious pseudoarguments made against evolution. Creationists try to cast doubt on the reality of evolution whenever a new fossil of a hominid is discovered. They crow that the latest fossil has a feature not found in living apes or living humans, meaning that it can't bridge the gap between the two groups. These arguments hardly call human evolution into doubt. The only lesson that should be drawn from them is that the term "missing link" should be retired for good.

Apparently so.

...Actually, this new Gallup report shows that 35% of people believe that Darwin's theory of evolution is not supported by the evidence, while another 29% don't know enough to say, and 1% have no opinion. So perhaps I should say, wrong or uninformed.

A little more horn-tooting: The Loom has just been named a winner of the American Association for the Advancement of Science's 2004 Science Journalism Award. The judges considered three pieces: Hamilton's Fall, Why the Cousins Are Gone, and My Darwinian Daughters. Here's the press release. Thanks to the judges--it's gratifying to see that it's possible for a little blog to swim with the big online sharks.

On the other hand, the news is a bit embarrassing, coming as it does while I've left the Loom woefully neglected over the past couple weeks. I've been working on a lot of articles, such as a piece for Science about the new hypothesis that our ancestors evolved to run. (Here's a shorter version; the full version will go online later today.)

Soul Made Flesh made Amazon.com's Editor's Pick list of the ten best science books of 2004. It's an honor, although it seems a little premature to call 2004 over!

Thanks to Wired for excerpting my post on what DNA has to say about one-man-one-woman marriage. When the editors told me that they were going to run the excerpt, I thought at first that it might be a bit stale by the time the magazine came out. But it seems today that the proper form of marriage is on the nation's mind again...

It's obvious from yesterday's vote that embryonic stem cells will continue to split the country (California versus Washington DC, for one thing). But in an ironic bit of timing researchers at the Reproductive Genetics Institute have just published some results at Reproductive BioMedicine Online that could--possibly--short-circuit some of the arguments against using embryonic stem cells.

The RGI researchers have figured out how to derive stem cells from a four-day old embryo--a stage known as a morula. Until now, scientists have been using older blastocysts, and have been destroying them in the process. But when the RGI team took a single cell from a morula, it still had the capacity to develop into a normal embryo. That means that parents who are doing IVF could conceivably agree to have a cell removed from their morula, which could then give rise to a line of stem cells, while the morula developed into an embryo ready for implanting. The stem cell line could be banked for therapy, or used for research.

I first read about this in an article published yesterday on News@Nature.com (unfortunately the article requires a subscription). Neither the article nor the abstract I linked to makes it clear whether this could be a viable source of stem cells for the large-scale research that scientists really want to do. But the results are enough to inspire a thought experiment.

Let's say you object to stem cell research because each blastocyst is a unique human being with a unique genome and the capacity for life. Destroying one is therefore murder. Would this "morula method" be acceptable to you? It seems like it has the benefits of adult stem cell research (no controversry over destroying embryos) and the benefits of embryonic stem cell research (the possibility of discovering therapies that can't be derived from adult stem cells). Or does any tinkering with embryos set off alarms? Perhaps we'll find out in a Senate hearing.